Gonna cut slits in my socks so I can wear them under my flip-flops. Or do you guys think that would look tacky?

We would do exactly that up here in Seattle!

For a few nights of 25 degrees etc, I wouldnt think anything inside the hull will freeze, the water temp is likely.... 60? not sure. Sure the safest route is to vacate the hoses.
Yeah.... I should have brought my long johns to FL in 2010... ice on the docks some mornings in February in Merritt Island!

__________________

__________________"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard

I'm up here in VT, not on the boat. I'm well aware of what cold weather can do to waterlines.

I really don't feel you need to worry about your water lines freezing as long as they're inside the boat. Even outside the boat, I'm not sure.

If you're going away for some time you might consider it. Or the boat is on the hard.

If the boat is in the water even though the air temp is 20 degrees, I doubt if the water temperature is ever below 50. That water heat sink will keep your boat well over 40 below decks. most I'd do is shut off the pumps and open the faucets. The head system should take care of itself.

A boat on the hard is a little different. Inside a boat wind chill isn't a problem. Just go with the actual temperature. My experience is that water will get slushy at around 32 or higher depending on other conditions. However, you need to be in the low twenties or high teens for a while to get the water to become the kind of ice that will really exert pressure on the lines. If you've shut off the pumps and opened the faucets what little ice expansion there is will be directed to the faucets. If you have a water pump disconnect it and let it drain the water is trapped in small spaces in the pump so expansion is limited.

Remember, even on the hard, although the air temperature will drop to the 20's for the evening the ground will still be above freezing and the boat will be warm during the day. I doubt if you'll see much below 30 degrees at night.

We're watching the manatees chew on the alga growing on the floating dock here in North Florida. They usually don't show here 'till the spring, but the water hasn't been cold.
Winter only skims by for a few days at a time. There's no mystery or anything unexpected and no need to take on any special defense for freezing. There may be some frost on the lawns ashore for a brief time, but the water doesn't get too cold and we keep our boats in the water all winter down here!

The joke last weekend in West Michigan was shorts and a lawnmower - 52 F.

You see, the fact is that we in Florida may not get the joke. When I grew up in Ft. Lauderdale the schools would be closed if the high temperature for the day was only 52 F, or anything less than 60F! We are raised as "pansies". If it's 52F we'll be wearing jackets and complaining.

In South Florida, Homes, schools, and churches did not have heat or airconditioning in the 1950's. Jacksonville, FL schools did not have airconditioners in the 1960's. Florida did not have a population or water problem until the airconditioners became affordable. Northerners spent their Summers further North, like Maine and Canada.

You see, the fact is that we in Florida may not get the joke. When I grew up in Ft. Lauderdale the schools would be closed if the high temperature for the day was only 52 F, or anything less than 60F! We are raised as "pansies". If it's 52F we'll be wearing jackets and complaining.

I lived in Fort Lauderdale, and we never had "snow" days, but we had several "cold days."

In the mid-19650's the rule was that if the temp went to 40 or below during the night, school would be closed. Almost all the hallways were outdoor hallways.

That was because so few children had warm clothing. We had just moved there, and my mom brought a little, but ... shoot, we were kids. We grew.

It was not economical to put any kind of heating system in the school (most homes didn't have AC and stores were just moving toward that). Without even a jacket that fit, we would freeze as kids.

So it didn't matter how warm it got during the day. If it went to 40 or below during the night, no school. Just too cold.

This winter has been very mild in west-central Florida. We've only had one hard freeze warining in Pinellas County. Last year, however, was a different story. Very cold for extended days at a time, right when the strawberry crop was ripening. The Way the farmers protected their strawberries was to spray the fields with water and coat them in ice.

They used up so much water that in some places they completely tapped out the underground water supply. Some people with home wells for their water supply had no water, and sink holes developed all over the place as the roofs of the empty natural reservoirs collapsed.

There were a LOT of sink holes, and guess what -- home insurance does not automatically protect from sink hole damage.